# Math Help - Volume Problem

1. ## Volume Problem

A cone with a base of radius r and height H is cut by a plane parallel to and h units above the base. Find the volume of the solid (frustrum of a cone) below the plane.

2. Originally Posted by kaiser0792
A cone with a base of radius r and height H is cut by a plane parallel to and h units above the base. Find the volume of the solid (frustrum of a cone) below the plane.
I assume since you posted this in the calculus section, you're looking for a solution involving a volume of revolution.

consider the line $y = \frac{r}{H} x$ rotated about the x-axis from $x = h$ to $x = H$

$V = \pi \int_h^H \left(\frac{r}{H} x\right)^2 \, dx
$